The invention relates to a conveyor with a conveyor train movable in a pipe by means of a linear motor drive, whereby the primary parts provided with coils are stationary, and the secondary parts are arranged on the conveyor train. Such conveyors can meet transport problems which, in difficult terrain, are only partially solved with conventional arrangements. For example, lines can be laid in riverbeds, in and/or on sand or rubble, in heavily settled urban areas, and in similar difficult areas.
Pipes are relatively easily handled, while at the same time they protect both material, as well as environment, and are therefore often used as means of transport for liquid and gaseous goods. However, if the goods delivered consist of solid granular material or piece goods, or if quantities delivered occur at irregular intervals, pipes alone do not meet the requirements. Therefore, additional transportable containers or a special conveyor system become necessary in the pipe. The usual hydraulic and pneumatic drives for this purpose are not economical for large quantities to be transported, heavy goods and long distances.
The magazine "Foerdern und Heben" (Deliver and Hoist), year of publication 20 (1970) No. 14, describes on pages 789 and 790 a conveyor with a linear motor arranged on top within the pipe to drive conveyor train cartridges which are guided along rails in the pipe. While it is true that this conveyor has a very good electric drive, due to the rails guiding the cartridge trains in the pipe, it is very involved and subject to breakdowns. The literature indicated also shows a belt conveyor arranged in the pipe, utilizing only a small portion of the pipe diameter.
It is, therefore, the object of this invention to provide a conveyor with conveyor trains driven by electro linear motors in a pipe which are simpler and more economical than heretofore. This is achieved by arranging the primary parts of the motor underneath the motor secondary with the latter attached to the bottom of the conveyor train. The conveyor train is stabilized against wobbling in the pipe by the fact that the center of gravity is located below the pipe center and, in addition, by utilizing the forces of attraction of the linear motor. Guide rails are, therefore, not necessary on a normal delivery line. This has not only advantages for safety in operation, as the conveyor train cannot get caught on any mounted parts, but also the arrangement permits a decrease in the pipe diameter corresponding to the throughput, since the pipes no longer have to be maintained by personnel from the inside. Therefore, lesser transport requirements may be met with the conveyor train in thin pipes. On account of the stationary arrangement of the primary motor parts, no sliding contacts are necessary, as is the case with trains with their own drive motors.
Utilization of the forces of attraction of the linear motor in connection with the center of gravity location below the pipe center as protection against wobbling encourages the construction of a light vehicle, consisting mainly of the motor secondary. These do not absolutely necessitate a tubular design but merely a slightly greater width than the iron package of the motor primary. Under the effect of centrifugal force in curves, a certain inclination of the train occurs despite the attraction forces of the linear motor. However, the vehicle also escapes the influence of the magnetic force, slows down and stabilizes again.
According to the invention, the motor primary lies flat, arranged in lower recesses and facing the secondary with their coils. Their sheet metal sections may be conformed to the curvature of the secondary part in a string fashion. The sheet metal sections are arranged in a string fashion. The sheet metal sections are arranged in a string and carry shared coils in their grooves. By fitting the primary parts to the secondary parts, the air gap is uniform and the degree of efficiency of the linear motor is high.
The distance between the individual primary sections along the path of travel is shorter than the length of the conveyor train provided with the secondary parts. Thus, at least one primary part is always effective. If the length of the train is about 300 m, for example, the motor primary sections are placed every 100 m. With inclines, the distances may also be shorter. They may also be provided with contact protection and designed so that in case of standstill of the conveyor train on the line caused by power failure, a momentary power line voltage increase to the .sqroot. 2-fold value becomes possible for twice the driving power.
As a further development of the invention, the conveyor train consists of individual connected parts supported in the pipe by means of support wheels or similar means, which are connected to each other via elastic clutches, or other adjacent elastic elements. The elasticity permits the passing of curves and switches and is not impaired by the secondary parts, which are joined together leaving only a slight distance. The advantage of this simple, light conveyor train is especially effective when the aluminum motor secondary parts--possibly supplemented by iron groundings which may form the basic frames for the parts and their wheels--are arranged as forms to receive further equipment for the vehicle. The adjacent front ends of the secondary parts and the iron groundings are rounded off, depending upon their approach during curves.
The carrier or tube for the goods delivered may also be an elastic pipe provided with a slot for loading and unloading on top, bound by sealing ridges, which are supported by annular springs placed at intervals and separable at the top. The slot for loading and unloading is slightly spread apart by a tool during loading, and by the delivered goods during unloading in an upside-down position, if the delivered goods lend themselves to trickling down, and if it is heavy enough. To this end, the conveyor train must drive onto a rail which has a 180.degree. spiral coil in travel direction, whereby the conveyor train is turned around with its opening pointing down. Unloading can also be done by means of suction or scooping by means of spoon-like tools at low speed without turning the conveyor train. Continuous quick loading and unloading reduces time and labor required, and reduces the length of the train for a specific problem.
As a carrier for delivered goods, the conveyor train may have an elastic conveyor belt which is divided into individual containers for delivered goods by delivered goods keepers, preventing sliding of the goods delivered on steep inclines. To prevent air stagnation before the conveyor train and suction or vacuum following the conveyor train, the pipe is provided with overflow apertures leading to a shared overflow pipe. These may in part be the initially mentioned recesses for the primary motor parts which are thereby provided with good cooling.
The conveyor train may have branch lines with swingable switches for joined pipes, or with an intermittent pipe which is brought before other pipes by bending it. These pipes may be provided with stops in order to correctly maintain the pipe alignment. In hexagonal arrangement of the pipes, six additional pipes may be connected with the main pipe. The swiveling pipe may also contain a primary part.
Several examples of the invention are represented on the drawings and explained as follows.